HTML and CSS Reference
Yo u s h o u l d c o n s t a n t l y l o o k a t m a k i n g c o n t e n t w o r k f o r a s m a n y u s e r s a s p o s -
Keeping graceful degradation/progressive enhancement in mind.
Providing alternatives for inaccessible content using built-in features
(e.g., alt text, transcripts for video).
Building in your own alternatives when no built-in mechanisms
exist (e.g., feature detection and provision of alternative styles using
Using polyfills to provide support for features where none exists.
The rule I used for deciding what to cover in this topic was to include a CSS3
feature only if it has support across at least two major browsers and if you can
make designs employing it work in older browsers that don't support it via polyfills,
alternative content, graceful degradation, and so on. I've broken this rule a few
times, but only when I thought a feature was very significant and likely to have
more implementations soon, and when nonsupport didn't completely break sites.
TIP: A great site to consult for quick summaries of which CSS3
and HTML5 features are ready to use on production sites, and
whether fallbacks and the like should be provided is http://html5please.us
by Divya Manian, Paul Irish, et al.